Summer without San Onofre is unlikely to bring outages, says state grid operator, helping change the perception of nuclear power

Number of homes San Onofre can power when it’s running at full capacity

This summer may be just a test run for operating Southern California’s electrical grid without a nuclear plant.

The latest report on the outage at the San Onofre Nuclear Generating Station shows the replacement of four massive steam generators was accompanied by serious design flaws, with no clear solution in sight.

Both stakeholders in San Onofre and critics of nuclear power say the start of a summer without the twin-reactor plant has forced a new accounting for the plant’s costs and benefits.

The utility industry and the state’s main grid operator are “considering a range of existing and new alternatives for mitigating the impacts of a long-term or permanent shutdown at San Onofre,” said Stephanie McCorkle, a spokeswoman for the California Independent System Operator.

At full tilt, San Onofre can produce enough electricity to power 1.4 million homes. The seaside plant, located at San Diego County’s northern edge, also provides crucial voltage to support the power flowing along coastal transmission routes.

Yet the grid operator foresees only the remote chance of rolling outages during hot weather in the next three months — when San Onofre is needed the most.

That assessment alone has changed perceptions of the plant as indispensable, said Dan Sullivan, president of San Diego-based Sullivan Solar Power, which employs 65 workers designing and installing solar arrays.

The plant shutdown — along with California’s aggressive renewable-energy policies and a newly completed transmission line into San Diego — have shifted the conversation about nuclear power.

The day is coming, Sullivan said, when “we can just say, ‘We’re done. We don’t need it anymore.’ ”

Others see that day as far away.

The power grid is being propped up this summer by two aging, heavily polluting natural gas generators at Huntington Beach — a resource that won’t be available again next summer.

Meeting electricity demands from now through September also could require that consumers conserve on short notice. Service interruptions may be scheduled among customers who took a rate reduction in return for possible disruptions.

“We’ve done a lot of things to get us to a reasonable state” of reliability for the summer, said Ted Craver, the CEO of Edison International, parent company to San Onofre operator Southern California Edison. “But they’re costly, either in terms of dollars and cents, or in terms of impact on our customers, or reliability of the system or pollution.

“I don’t think you’d want to run that way on a long-term basis — we wouldn’t.”

Long-range alternatives to San Onofre involve complex calculations linked to state mandates for improved air quality and for phasing out most coastal power plants that pump in ocean water for “once-through” cooling.

The grid also must adapt to steep state requirements for more renewable energy generation — power that, unlike nuclear energy, can fluctuate with each day’s wind and sunshine.

Private investors along with utility customers still have a major economic stake in the plant’s future.